It is estimated that 40% of the United States adult population suffers from hypertension. (The American Heart Association guidelines indicate hypertension exists when the blood pressure is greater than 140/90 mm Hg.) Fifty percent of hypertension is believed linked to salt sensitivity. However, the degree to which sodium intake and hypertension are linked in cause-effect relationship has long been disputed. It is known that many hypertensive individuals respond to decrease in dietary sodium intake by decrease in blood pressure. It is also known that some hypertensive individuals fail to respond favorably to restricted salt diet. Some have recommended moderate dietary salt restriction for all patients. Restriction of salt is not without danger, particularly during hot weather or strenuous exercise. The failure of salt restrictions to control hypertension most likely arises from indiscriminate implementation of the restricted salt/sodium diet. Prediction of the effect of restriction of sodium intake in any particular patient may be an important factor in determining treatment protocol for the patient. Previously a patient was deemed salt-sensitive if (SBP-DBP).div.3+(DBP) where SBP is systolic blood pressure and DBP is diastolic blood pressure showed &gt;10 mm Hg increase in response to an administration of sodium chloride in amounts higher than the customary intake subsequent to administration of sodium chloride after depletion. (Causes of depletion may include administration of diuretic agents or severe dietary restrictions.) Methods of evaluation using these criteria were not found to be readily applicable. Failure to reflect customary habits and diet were probably factors that decreased applicability of the evaluative methods previously used.